[j1nx]

1st figure out under which user the tvheadend is running;

#ps ax | grep tvheadend

You will get out such as;

2140 ? Ssl 3:55 /usr/bin/tvheadend -f -u hts -g video
32238 pts/1 R+ 0:00 grep --color=auto tvheadend

There you will see, it runs as user "hts" (-u hts)

Go into the hts config folder for that user;

cd /home/hts/.hts/tvheadend/

Here are all setting stored. But also the config of the super user. You need to be root, so under ubuntu for instance;

sudo cat superuser

You will get an output like;

{
"username": "gsi095",
"password": "forgotthedamnthing"
}

Use those to get into the webadmin and do your things.